Jack.



' T. J. SMITH WIGK.

JACK.

APPLICATION FILED JUNE 9, 1910.

980,845. Patented Jan.3,191'1.

THE NORRIS PETERS 50.. wAsgm-imu, D. c.

THOMAS J. SMITHWICK, OF MOUNT AIRY, NORTH CAROLINA.

JACK.

Specification of Letters Patent.

Patented J an. 3, 1911.

Application filed June 9, 1910. Serial No. 566,100.

To all whom "it may concern:

Be it known that I, THOMAS J. SMITH- wrox, a citizen of the United States, residing at Mount Airy, in the county of Surry, State of North Carolina, have invented certain new and useful Improvements in Jacks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to jacks and has special reference to a jack of the screw type.

The principal object of the invention is to provide a simple, light and eflicient jack of improved construction adapted to be used by carpenters, machinists and others for the purpose of alining timbers, setting up engines and machinery and other similar work.

The invention consists in general of certain novel details of construction and combinations of parts hereinafter fully described, illustrated in the accompanying drawings, and specifically set forth in the claim.

In the accompanying drawings, like characters of reference indicate like parts in the several views, and :F igure 1 is a side elevation of a jack constructed in accordance with this invention. Fig. 2 is a vertical section therethrough. 3 is a top plan view of the jack.

This jack comprises a base having a centrally disposed boss 11 formed on its upper side and this base and boss are of relatively low height. Extending centrally through the base and boss is a vertically disposed threaded aperture 12 wherein is held the lower end 13 of an elevating screw, said lower end being threaded to correspond with the threaded opening in the base and boss. This elevating screw is several times as long as the height of the base so that when the device is screwed down the elevating screw will project below the bottom of the base. Above the threaded portion 13 i 14 the upper end 5 an enlarged hexagonal nut of which is circular, the hexagonal andL circular portions merging This nut is provided with lever receiving openings 15 extending diametrically through the nut and arranged in stepped relation as can clearly be seen by reference to Fig. 1. Above the nut 14 the elevating screw is provided with a reduced cylindrical upper end 16 on which is held an anti-friction washer 17, the washer resting on said nut. On this into each other.v

reduced end 16 is a cap 18 having a centrally disposed opening 19 fitting said reduced end. This cap is furthermore provided with an enlarged cylindrical recess 20 forming the upper end of this opening 19 and the proportions of the parts are such that when the device is assembled the bottom of the recess 20 lies in substantially the same plane as the top of the reduced end 16. In the recess 20 is held a washer 21 of less thickness than the depth of said recess and fitting snugly therein. This washer rests on the reduced end 16 and a screw 22 is countersunk in-the washer and screwed into said reduced end so that neither the washer nor the screw projects above the upper surface of the cap 18. The upper surface of the cap 18 is roughened by grooves 23 intersecting each other for the purpose of better gripping the material to which the device may be applied. The cap 18 is furthermore provided with a radial oil hole 24 having a downwardly extending branch 25 and the radial portion of this oil hole serves to admit lubrication to the cylindrical end 16 while the downwardly extending branch lubricates the anti-friction washer 17. In the base 10 are provided screw receiving openings 26 by means of which the jack may be held stationary on a timber or the like while the screwing operation is being performed.

In the operation of this device either a wrench is applied to the nut or a bar is in.- serted in one of the openings 15 and the screw turned around in the usual manner.

It is to be noted that by reason of the low base the device may be used in very close quarters while the great length of the screw in comparison will enable a wide range of adjustment to be obtained.

There has thus been provided a simple and eflicient device of the kind described and for the purpose specified.

I-laving thus described the invention, what claimed as new, is

A jack comprising a base having a centrally disposed boss, said base and boss bc ing of relatively low height and having a centrally disposed threaded aperture extending vertically therethrough; an elevating screw having a lower threading end of a length several times the height of the base and boss, an enlarged hexagonal nut at the upper end of the threaded portion provided with lever receiving openings extending diametrically through the nut and arranged in stepped relation, and :1 reduced cylindrical f upper end; an enti-fricti0n Washer held on said upper end and resting on said nut; a cap having a centrally dispos d opening fitting said reduced end endprovided with an en larged recess at its upper extremity the hot tern of the recess lying iin substantially the same plane as the top of the reduced end; a second Washer of less thickness than the depth of said recess fitting in the recess and resting on the reduced end; and a screw countersunk in the Washer and screwed into said reduced end.

In testimony whereof, I aflix my signw ture, in presence of two Witnesses.

THOMAS J. SMHI'WVIGK.

Witnesses l. W. BARBER, TV. SAUNDERS. 

